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Characterization of antithrombin isoforms and latent forms by ion exchange chromatography coupled to mass spectrometry. Anal Biochem 2023; 668:115088. [PMID: 36878338 DOI: 10.1016/j.ab.2023.115088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 01/16/2023] [Accepted: 02/21/2023] [Indexed: 03/07/2023]
Abstract
Antithrombin is a key protein of the coagulation system belonging to the serine protease inhibitor family. Antithrombin preparations are used as a therapeutic treatment for patients with decreased antithrombin activity. Elucidating the structural features of this protein is an important part of the control strategy to assure a high quality. This study presents an ion exchange chromatographic method coupled to mass spectrometry capable of characterizing antithrombin post-translational modifications such as N-glycosylation, phosphorylation or deamidation. Furthermore, the method was successfully used to evidence irreversible/inactive conformers of antithrombin which are commonly observed for serine protease inhibitors and referred to as latent forms.
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Investigation of monoclonal antibody dimers in a final formulated drug by separation techniques coupled to native mass spectrometry. MAbs 2021; 12:e1781743. [PMID: 32633190 PMCID: PMC7531515 DOI: 10.1080/19420862.2020.1781743] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Therapeutic monoclonal antibodies (mAbs) are highly complex proteins that must be exhaustively characterized according to the regulatory authorities' recommendations. MAbs display micro-heterogeneity mainly due to their post-translational modifications, but also to their susceptibility to chemical and physical degradations. Among these degradations, aggregation is quite frequent, initiated by protein denaturation and then dimer formation. Here, we investigated the nature and structure of the high molecular weight species (HMW) present at less than 1% in an unstressed formulated roledumab biopharmaceutical, as a model of high purity mAb. HMW species were first purified through preparative size-exclusion chromatography (SEC) and then analyzed by a combination of chromatographic methods (ion-exchange chromatography (IEX), SEC) coupled to native mass spectrometry (MS), as well as sodium dodecyl sulfate–polyacrylamide gel electrophoresis and capillary gel electrophoresis under non-reducing conditions. Both covalently and non-covalently bound dimers were identified at a proportion of 50/50. In-depth characterization of the HMW fraction by SEC and IEX hyphenated to native MS revealed the presence of three mAb dimer forms having the same mass, but differing by their charge and size. They were attributed to different compact and elongated dimers. Finally, high-resolution middle-up approaches using different enzymes (IdeS and IgdE) were performed to determine the mAb domains implicated in the dimerization. Our results revealed that the roledumab dimers were associated mainly by a single Fab-to-Fab arm-bound association.
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C-terminal lysine clipping of IgG1: impact on binding to human FcγRIIIa and neonatal Fc receptors. Eur J Pharm Sci 2021; 159:105730. [PMID: 33493670 DOI: 10.1016/j.ejps.2021.105730] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 01/12/2021] [Accepted: 01/18/2021] [Indexed: 01/01/2023]
Abstract
Monoclonal antibodies (mAbs) display numerous structural attributes, some of them may impact their safety and/or efficacy profiles. C-terminal lysine clipping is a common phenomenon occurring during the bioproduction of mAbs and leads to variable amounts of final process-related charge variants. If Fc-glycosylation has been by far the most documented critical quality attribute (CQA), the potential impacts of mAb C-terminal lysine content is far less reported, particularly on the ability of these basic variants to bind human Fc receptors. To address this question, three charge variant species having zero (K0), one (K1) and two (K2) C-terminal lysine(s) were isolated with high purity from an in-house human IgG1 by preparative strong-cation exchange (SCX) chromatography. A comprehensive biophysical characterization of these three fractions was undertaken, demonstrating their high similarity in terms of structural homogeneity, with a particular attention paid on their respective N-glycosylation profiles. The binding affinity of the fractions to human FcγRIIIa-Val176 was assessed both by affinity chromatography and surface plasmon resonance (SPR), and to human neonatal Fc receptor (FcRn) by affinity chromatography. Results demonstrate that the three charge variants did not show any significant binding difference for the two tested human Fc receptors, translating certainly to comparable biological properties. As a consequence, C-terminal lysine clipping of the present therapeutic IgG1 should not impact both FcRn-dependent pharmacokinetic profiles and FcγRIIIa-driven cytotoxic activities. The methods used in this study can be widely applied to other IgG1 to define criticality of the C-terminal lysine clipping as a CQA.
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Human serum albumin presents isoform variants with altered neonatal Fc receptor interactions. Protein Sci 2020; 28:1982-1992. [PMID: 31583777 DOI: 10.1002/pro.3733] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 09/09/2019] [Accepted: 09/18/2019] [Indexed: 12/23/2022]
Abstract
Human serum albumin (HSA) is the most abundant protein in plasma and presents the particularity, with IgG, to have an extraordinary long serum half-life conferred by its interaction with the neonatal Fc receptor (FcRn). If the impact of IgG post-translational modifications (PTMs) on FcRn binding is well documented, it is far less reported for HSA despite numerous PTMs occurring on the protein in plasma. HSA is susceptible to numerous degradation reactions in plasma, because of aging, oxidative stress or liver and pancreas related pathologies. In the present study, we combined FcRn affinity chromatography and mass spectrometry to investigate the impact of HSA PTMs upon FcRn binding. This methodology presents the advantage to distinguish the effect of a single modification from a plasma HSA preparation made of a mixture of different isoforms. Cys34 oxidation, Lys525 glycation, and Leu585 C-terminal truncation, which are modifications related to several pathological conditions, were demonstrated to act negatively on HSA-FcRn interaction. The HSA-FcRn binding alteration generated by these modifications is consistent with their vicinity with the interaction interface of the two proteins. Results were discussed regarding altered half-life of HSA observed in several disease states and pave the way toward new understandings of the hypoalbuminemia pathogenesis. SIGNIFICANCE STATEMENT: In this study, we investigated the impact of several post-translational modifications of HSA toward its ability to bind to the neonatal Fc receptor using in vitro affinity chromatography, mass spectrometry, and surface plasmon resonance. Cys34 oxidation, Lys525 glycation, and Leu585 C-terminal truncation were demonstrated to decrease HSA-FcRn binding. These modifications occurring in circulating HSA were discussed in relation to several pathologies as well as for the use of HSA as a therapeutic protein.
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Development and validation of the mental health professional culture inventory. Epidemiol Psychiatr Sci 2019; 29:e80. [PMID: 31839026 PMCID: PMC8061147 DOI: 10.1017/s2045796019000787] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 10/02/2019] [Accepted: 10/30/2019] [Indexed: 12/03/2022] Open
Abstract
AIMS No instrument has been developed to explicitly assess the professional culture of mental health workers interacting with severely mentally ill people in publicly or privately run mental health care services. Because of theoretical and methodological concerns, we designed a self-administered questionnaire to assess the professional culture of mental health services workers. The study aims to validate this tool, named the Mental Health Professional Culture Inventory (MHPCI). The MHPCI adopts the notion of 'professional culture' as a hybrid construct between the individual and the organisational level that could be directly associated with the professional practices of mental health workers. METHODS The MHPCI takes into consideration a multidimensional definition of professional culture and a discrete number of psychometrically derived dimensions related to meaningful professional behaviour. The questionnaire was created and developed by a conjoint Italian-Canadian research team with the purpose of obtaining a fully cross-cultural questionnaire and was pretested in a pilot study. Subsequently, a validation survey was conducted in northern Italy and in Canada (Montreal area, Quebec). Data analysis was conducted in different steps designed to maximise the cross-cultural adaptation of the questionnaire through a recursive procedure consisting of performing a principal component analysis (PCA) on the Italian sample (N = 221) and then testing the resulting factorial model on the Canadian sample (N = 237). Reliability was also assessed with a test-retest design. RESULTS Four dimensions emerged in the PCA and were verified in the confirmatory factor analysis: family involvement, users' sexuality, therapeutic framework and management of aggression risk. All the scales displayed good internal consistency and reliability. CONCLUSIONS This study suggests the MHPCI could be a valid and reliable instrument to measure the professional behaviour of mental health services workers. The content of the four scales is consistent with the literature on psychosocial rehabilitation, suggesting that the instrument could be used to evaluate staff behaviour regarding four crucial dimensions of mental health care.
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Characterization of Human Serum Albumin isoforms by ion exchange chromatography coupled on-line to native mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2018; 1095:87-93. [DOI: 10.1016/j.jchromb.2018.07.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Revised: 07/11/2018] [Accepted: 07/13/2018] [Indexed: 10/28/2022]
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Middle-up analysis of monoclonal antibodies after combined IgdE and IdeS hinge proteolysis: Investigation of free sulfhydryls. J Pharm Biomed Anal 2018; 149:541-546. [DOI: 10.1016/j.jpba.2017.11.046] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 11/10/2017] [Accepted: 11/19/2017] [Indexed: 11/28/2022]
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Biochemical characterization of LR769, a new recombinant factor VIIa bypassing agent produced in the milk of transgenic rabbits. Haemophilia 2017; 23:e324-e334. [PMID: 28594467 DOI: 10.1111/hae.13253] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/01/2017] [Indexed: 11/29/2022]
Abstract
BACKGROUND The bypassing agent factor VII (FVIIa) is a first-line therapy for the treatment of acute bleeding episodes in patients with haemophilia and high-titre inhibitors. FVIIa is a highly post-translationally modified protein that requires eukaryotic expression systems to produce a fully active molecule. A recombinant FVIIa was produced in the milk of transgenic rabbits to increase expression and provide an efficient, safe and affordable product after purification to homogeneity (LR769). AIM To present the biochemical and functional in vitro characteristics of LR769. RESULTS Mass spectrometric analyses of the intact protein and of heavy and light chains revealed a fully activated, mature and properly post-translationally modified protein notably regarding N/O-glycosylations and γ-carboxylation. Primary structure analysis, performed by peptide mapping, confirmed 100% of the sequence and the low level or absence of product-derived impurities such as oxidized, deamidated and glycated forms. Low levels of aggregates and fragments were observed by different chromatographic methods. Higher order structure investigated by circular dichroism showed appropriate secondary/tertiary structures and conformational change in the presence of Ca2+ ions. Finally, activated partial thromboplastin time and thrombin generation assays showed the ability of LR769 to decrease coagulation time and to generate thrombin in haemophiliac-A-plasmas, even in the presence of inhibitors. CONCLUSION The innovative expression system used to produce LR769 yields a new safe and effective rhFVIIa for the treatment of haemophilia A or B patients with inhibitors.
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Glycation of polyclonal IgGs: Effect of sugar excipients during stability studies. Eur J Pharm Biopharm 2016; 102:185-90. [DOI: 10.1016/j.ejpb.2016.03.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 03/07/2016] [Accepted: 03/14/2016] [Indexed: 10/22/2022]
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Trauma Association of Canada (TAC) Annual Scientific Meeting. The Westin Whistler Resort & Spa, Whistler, BC, Thursday, Apr. 11 to Saturday, Apr. 13, 2013Testing the reliability of tools for pediatric trauma teamwork evaluation in a North American high-resource simulation settingThe association of etomidate with mortality in trauma patientsDefinition of isolated hip fractures as an exclusion criterion in trauma centre performance evaluations: a systematic reviewEstimation of acute care hospitalization costs for trauma hospital performance evaluation: a systematic reviewHospital length of stay following admission for traumatic injury in Canada: a multicentre cohort studyPredictors of hospital length of stay following traumatic injury: a multicentre cohort studyInfluence of the heterogeneity in definitions of an isolated hip fracture used as an exclusion criterion in trauma centre performance evaluations: a multicentre cohort studyPediatric trauma, advocacy skills and medical studentsCompliance with the prescribed packed red blood cell, fresh frozen plasma and platelet ratio for the trauma transfusion pathway at a level 1 trauma centreEarly fixed-wing aircraft activation for major trauma in remote areasDevelopment of a national, multi-disciplinary trauma crisis resource management curriculum: results from the pilot courseThe management of blunt hepatic trauma in the age of angioembolization: a single centre experienceEarly predictors of in-hospital mortality in adult trauma patientsThe impact of open tibial fracture on health service utilization in the year preceding and following injuryA systematic review and meta-analysis of the efficacy of red blood cell transfusion in the trauma populationSources of support for paramedics managing work-related stress in a Canadian EMS service responding to multisystem trauma patientsAnalysis of prehospital treatment of pain in the multisystem trauma patient at a community level 2 trauma centreIncreased mortality associated with placement of central lines during trauma resuscitationChronic pain after serious injury — identifying high risk patientsEpidemiology of in-hospital trauma deaths in a Brazilian university teaching hospitalIncreased suicidality following major trauma: a population-based studyDevelopment of a population-wide record linkage system to support trauma researchInduction of hmgb1 by increased gut permeability mediates acute lung injury in a hemorrhagic shock and resuscitation mouse modelPatients who sustain gunshot pelvic fractures are at increased risk for deep abscess formation: aggravated by rectal injuryAre we transfusing more with conservative management of isolated blunt splenic injury? A retrospective studyMotorcycle clothesline injury prevention: Experimental test of a protective deviceA prospective analysis of compliance with a massive transfusion protocol - activation alone is not enoughAn evaluation of diagnostic modalities in penetrating injuries to the cardiac box: Is there a role for routine echocardiography in the setting of negative pericardial FAST?Achievement of pediatric national quality indicators — an institutional report cardProcess mapping trauma care in 2 regional health authorities in British Columbia: a tool to assist trauma sys tem design and evaluationPatient safety checklist for emergency intubation: a systematic reviewA standardized flow sheet improves pediatric trauma documentationMassive transfusion in pediatric trauma: a 5-year retrospective reviewIs more better: Does a more intensive physiotherapy program result in accelerated recovery for trauma patients?Trauma care: not just for surgeons. Initial impact of implementing a dedicated multidisciplinary trauma team on severely injured patientsThe role of postmortem autopsy in modern trauma care: Do we still need them?Prototype cervical spine traction device for reduction stabilization and transport of nondistraction type cervical spine injuriesGoing beyond organ preservation: a 12-year review of the beneficial effects of a nonoperative management algorithm for splenic traumaAssessing the construct validity of a global disability measure in adult trauma registry patientsThe mactrauma TTL assessment tool: developing a novel tool for assessing performance of trauma traineesA quality improvement approach to developing a standardized reporting format of ct findings in blunt splenic injuriesOutcomes in geriatric trauma: what really mattersFresh whole blood is not better than component therapy (FFP:RBC) in hemorrhagic shock: a thromboelastometric study in a small animal modelFactors affecting mortality of chest trauma patients: a prospective studyLong-term pain prevalence and health related quality of life outcomes for patients enrolled in a ketamine versus morphine for prehospital traumatic pain randomized controlled trialDescribing pain following trauma: predictors of persistent pain and pain prevalenceManagement strategies for hemorrhage due to pelvic trauma: a survey of Canadian general surgeonsMajor trauma follow-up clinic: Patient perception of recovery following severe traumaLost opportunities to enhance trauma practice: culture of interprofessional education and sharing among emergency staffPrehospital airway management in major trauma and traumatic brain injury by critical care paramedicsImproving patient selection for angiography and identifying risk of rebleeding after angioembolization in the nonoperative management of high grade splenic injuriesFactors predicting the need for angioembolization in solid organ injuryProthrombin complex concentrates use in traumatic brain injury patients on oral anticoagulants is effective despite underutilizationThe right treatment at the right time in the right place: early results and associations from the introduction of an all-inclusive provincial trauma care systemA multicentre study of patient experiences with acute and postacute injury carePopulation burden of major trauma: Has introduction of an organized trauma system made a difference?Long-term functional and return to work outcomes following blunt major trauma in Victoria, AustraliaSurgical dilemma in major burns victim: heterotopic ossification of the tempromandibular jointWhich radiological modality to choose in a unique penetrating neck injury: a differing opinionThe Advanced Trauma Life Support (ATLS) program in CanadaThe Rural Trauma Team Development Course (RTTDC) in Pakistan: Is there a role?Novel deployment of BC mobile medical unit for coverage of BMX world cup sporting eventIncidence and prevalence of intra-abdominal hypertension and abdominal compartment syndrome in critically ill adults: a systematic review and meta-analysisRisk factors for intra-abdominal hypertension and abdominal compartment syndrome in critically ill or injured adults: a systematic review and meta-analysisA comparison of quality improvement practices at adult and pediatric trauma centresInternational trauma centre survey to evaluate content validity, usability and feasibility of quality indicatorsLong-term functional recovery following decompressive craniectomy for severe traumatic brain injuryMorbidity and mortality associated with free falls from a height among teenage patients: a 5-year review from a level 1 trauma centreA comparison of adverse events between trauma patients and general surgery patients in a level 1 trauma centreProcoagulation, anticoagulation and fibrinolysis in severely bleeding trauma patients: a laboratorial characterization of the early trauma coagulopathyThe use of mobile technology to facilitate surveillance and improve injury outcome in sport and physical activityIntegrated knowledge translation for injury quality improvement: a partnership between researchers and knowledge usersThe impact of a prevention project in trauma with young and their learningIntraosseus vascular access in adult trauma patients: a systematic reviewThematic analysis of patient reported experiences with acute and post-acute injury careAn evaluation of a world health organization trauma care checklist quality improvement pilot programProspective validation of the modified pediatric trauma triage toolThe 16-year evolution of a Canadian level 1 trauma centre: growing up, growing out, and the impact of a booming economyA 20-year review of trauma related literature: What have we done and where are we going?Management of traumatic flail chest: a systematic review of the literatureOperative versus nonoperative management of flail chestEmergency department performance of a clinically indicated and technically successful emergency department thoracotomy and pericardiotomy with minimal equipment in a New Zealand institution without specialized surgical backupBritish Columbia’s mobile medical unit — an emergency health care support resourceRoutine versus ad hoc screening for acute stress: Who would benefit and what are the opportunities for trauma care?A geographical analysis of the Early Development Instrument (EDI) and childhood injuryDevelopment of a pediatric spinal cord injury nursing course“Kids die in driveways” — an injury prevention campaignEpidemiology of traumatic spine injuries in childrenA collaborative approach to reducing injuries in New Brunswick: acute care and injury preventionImpact of changes to a provincial field trauma triage tool in New BrunswickEnsuring quality of field trauma triage in New BrunswickBenefits of a provincial trauma transfer referral system: beyond the numbersThe field trauma triage landscape in New BrunswickImpact of the Rural Trauma Team Development Course (RTTDC) on trauma transfer intervals in a provincial, inclusive trauma systemTrauma and stress: a critical dynamics study of burnout in trauma centre healthcare professionalsUltrasound-guided pediatric forearm fracture reduction with sedation in the emergency departmentBlock first, opiates later? The use of the fascia iliaca block for patients with hip fractures in the emergency department: a systematic reviewRural trauma systems — demographic and survival analysis of remote traumas transferred from northern QuebecSimulation in trauma ultrasound trainingIncidence of clinically significant intra-abdominal injuries in stable blunt trauma patientsWake up: head injury management around the clockDamage control laparotomy for combat casualties in forward surgical facilitiesDetection of soft tissue foreign bodies by nurse practitioner performed ultrasoundAntihypertensive medications and walking devices are associated with falls from standingThe transfer process: perspectives of transferring physiciansDevelopment of a rodent model for the study of abdominal compartment syndromeClinical efficacy of routine repeat head computed tomography in pediatric traumatic brain injuryEarly warning scores (EWS) in trauma: assessing the “effectiveness” of interventions by a rural ground transport service in the interior of British ColumbiaAccuracy of trauma patient transfer documentation in BCPostoperative echocardiogram after penetrating cardiac injuries: a retrospective studyLoss to follow-up in trauma studies comparing operative methods: a systematic reviewWhat matters where and to whom: a survey of experts on the Canadian pediatric trauma systemA quality initiative to enhance pain management for trauma patients: baseline attitudes of practitionersComparison of rotational thromboelastometry (ROTEM) values in massive and nonmassive transfusion patientsMild traumatic brain injury defined by GCS: Is it really mild?The CMAC videolaryngosocpe is superior to the glidescope for the intubation of trauma patients: a prospective analysisInjury patterns and outcome of urban versus suburban major traumaA cost-effective, readily accessible technique for progressive abdominal closureEvolution and impact of the use of pan-CT scan in a tertiary urban trauma centre: a 4-year auditAdditional and repeated CT scan in interfacilities trauma transfers: room for standardizationPediatric trauma in situ simulation facilitates identification and resolution of system issuesHospital code orange plan: there’s an app for thatDiaphragmatic rupture from blunt trauma: an NTDB studyEarly closure of open abdomen using component separation techniqueSurgical fixation versus nonoperative management of flail chest: a meta-analysisIntegration of intraoperative angiography as part of damage control surgery in major traumaMass casualty preparedness of regional trauma systems: recommendations for an evaluative frameworkDiagnostic peritoneal aspirate: An obsolete diagnostic modality?Blunt hollow viscus injury: the frequency and consequences of delayed diagnosis in the era of selective nonoperative managementEnding “double jeopardy:” the diagnostic impact of cardiac ultrasound and chest radiography on operative sequencing in penetrating thoracoabdominal traumaAre trauma patients with hyperfibrinolysis diagnosed by rotem salvageable?The risk of cardiac injury after penetrating thoracic trauma: Which is the better predictor, hemodynamic status or pericardial window?The online Concussion Awareness Training Toolkit for health practitioners (CATT): a new resource for recognizing, treating, and managing concussionThe prevention of concussion and brain injury in child and youth team sportsRandomized controlled trial of an early rehabilitation intervention to improve return to work Rates following road traumaPhone call follow-upPericardiocentesis in trauma: a systematic review. Can J Surg 2013. [DOI: 10.1503/cjs.005813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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Abstract
Detection of very intense short radio bursts from Neptune was possible as early as 30 days before closest approach and at least 22 days after closest approach. The bursts lay at frequencies in the range 100 to 1300 kilohertz, were narrowband and strongly polarized, and presumably originated in southern polar regions ofthe planet. Episodes of smooth emissions in the frequency range from 20 to 865 kilohertz were detected during an interval of at least 10 days around closest approach. The bursts and the smooth emissions can be described in terms of rotation in a period of 16.11 +/- 0.05 hours. The bursts came at regular intervals throughout the encounter, including episodes both before and after closest approach. The smooth emissions showed a half-cycle phase shift between the five episodes before and after closest approach. This experiment detected the foreshock of Neptune's magnetosphere and the impacts of dust at the times of ring-plane crossings and also near the time of closest approach. Finally, there is no evidence for Neptunian electrostatic discharges.
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Abstract
Within distances to Uranus of about 6 x 10(6) kilometers (inbound) and 35 x 10(6) kilometers (outbound), the planetary radio astronomy experiment aboard Voyager 2 detected a wide variety of radio emissions. The emission was modulated in a period of 17.24 +/- 0.01 hours, which is identified as the rotation period of Uranus' magnetic field. Of the two poles where the axis of the off-center magnetic dipole (measured by the magnetometer experiment aboard Voyager 2) meets the planetary surface, the one closer to dipole center is now located on the nightside of the planet. The radio emission generally had maximum power and bandwidth when this pole was tipped toward the spacecraft. When the spacecraft entered the nightside hemisphere, which contains the stronger surface magnetic pole, the bandwidth increased dramatically and thereafter remained large. Dynamically evolving radio events of various kinds embedded in these emissions suggest a Uranian magnetosphere rich in magnetohydrodynamic phenomena.
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Manufacturing of prototype components for the ITER divertor baffle. FUSION ENGINEERING AND DESIGN 2003. [DOI: 10.1016/s0920-3796(03)00389-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Design and reactivity of topologically unique, chiral phosphonamides. Remarkable diastereofacial selectivity in asymmetric olefination and alkylation. J Am Chem Soc 2002. [DOI: 10.1021/ja00331a070] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
Ground-based observations have shown that Jupiter is a two-component source of microwave radio emission: thermal atmospheric emission and synchrotron emission from energetic electrons spiralling in Jupiter's magnetic field. Later in situ measurements confirmed the existence of Jupiter's high-energy electron-radiation belts, with evidence for electrons at energies up to 20[?]MeV. Although most radiation belt models predict electrons at higher energies, adiabatic diffusion theory can account only for energies up to around 20[?]MeV. Unambiguous evidence for more energetic electrons is lacking. Here we report observations of 13.8[?]GHz synchrotron emission that confirm the presence of electrons with energies up to 50[?]MeV; the data were collected during the Cassini fly-by of Jupiter. These energetic electrons may be repeatedly accelerated through an interaction with plasma waves, which can transfer energy into the electrons. Preliminary comparison of our data with model results suggests that electrons with energies of less than 20[?]MeV are more numerous than previously believed.
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Application of rat hepatocyte culture to predict in vivo metabolic auto-induction: studies with DFP, a cyclooxygenase-2 inhibitor. Drug Metab Dispos 2001; 29:159-65. [PMID: 11159806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
The drug candidate DFP [5,5-dimethyl-3-(2-isopropoxy)-4-(4-methanesulfonylphenyl)-2(5H)-furanone] is a selective cyclooxygenase-2 inhibitor under evaluation for analgesic and anti-inflammatory therapy. The in vitro metabolic pathways (rat microsomes) involve hydroxylation of the isopropyl side chain at either of two positions, the methyl or the methine, thus producing a hydroxylated metabolite (DFHP) or a dealkylated metabolite (DFH). DFH formation was the major pathway. Using hepatic microsomes from rats treated with agents that induce specific CYP isozymes, it was shown that the dexamethasone-inducible rat CYP3A isozyme(s) play a major role in DFH formation. The roles of CYP3A1 and -3A2 were confirmed with genetically engineered rat CYP enzymes. The potential for induction of rat CYP3A by DFP was evaluated by incubating DFP in rat hepatocyte cultures and measuring the CYP3A levels. Both CYP3A immunoreactive protein and enzyme activity were induced in a dose-dependent manner. The induction was confirmed in vivo by dosing rats with DFP at 100 mg/kg for 4 days. Microsomes prepared from the excised livers showed that DFP gave approximately 55% of the induction observed with dexamethasone, as determined by Western blot. In vitro metabolic auto-induction of DFP was assessed by measuring the metabolism of DFP in hepatocytes treated with DFP. DFH formation was significantly enhanced in the DFP-treated cells. In vivo, treating rats with DFP at doses of 10 to 100 mg/(kg.day) for 13 weeks indicated that DFP induced its own metabolism. The C(max) and plasma drug area under the curve values during the thirteenth week were significantly lower than that on the first day, and the effect was dose-dependent.
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SAR in the alkoxy lactone series: the discovery of DFP, a potent and orally active COX-2 inhibitor. Bioorg Med Chem Lett 1999; 9:2207-12. [PMID: 10465547 DOI: 10.1016/s0960-894x(99)00365-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Extensive SAR has been established in the alkoxy lactone series and this has lead to the discovery of DFP (5,5-dimethyl-3-(2-propoxy)-4-methanesulfonylphenyl)-2(5H)-furanon e), a potent COX-2 inhibitor exhibiting in vivo efficacy in all models studied.
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Rofecoxib [Vioxx, MK-0966; 4-(4'-methylsulfonylphenyl)-3-phenyl-2-(5H)-furanone]: a potent and orally active cyclooxygenase-2 inhibitor. Pharmacological and biochemical profiles. J Pharmacol Exp Ther 1999; 290:551-60. [PMID: 10411562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023] Open
Abstract
The discoveries that cyclooxygenase (COX)-2 is an inducible form of COX involved in inflammation and that COX-1 is the major isoform responsible for the production of prostaglandins (PGs) in the gastrointestinal tract have provided a rationale for the development of specific COX-2 inhibitors as a new class of anti-inflammatory agents with improved gastrointestinal tolerability. In the present study, the preclinical pharmacological and biochemical profiles of rofecoxib [Vioxx, also known as MK-0966, 4-(4'-methylsulfonylphenyl)-3-phenyl-2-(5H)-furanone], an orally active COX-2 inhibitor, are described. Rofecoxib is a potent inhibitor of the COX-2-dependent production of PGE(2) in human osteosarcoma cells (IC(50) = 26 +/- 10 nM) and Chinese hamster ovary cells expressing human COX-2 (IC(50) = 18 +/- 7 nM) with a 1000-fold selectivity for the inhibition of COX-2 compared with the inhibition of COX-1 activity (IC(50) > 50 microM in U937 cells and IC(50) > 15 microM in Chinese hamster ovary cells expressing human COX-1). Rofecoxib is a time-dependent inhibitor of purified human recombinant COX-2 (IC(50) = 0.34 microM) but caused inhibition of purified human COX-1 in a non-time-dependent manner that could only be observed at a very low substrate concentration (IC(50) = 26 microM at 0.1 microM arachidonic acid concentration). In an in vitro human whole blood assay, rofecoxib selectively inhibited lipopolysaccharide-induced, COX-2-derived PGE(2) synthesis with an IC(50) value of 0.53 +/- 0.02 microM compared with an IC(50) value of 18.8 +/- 0.9 microM for the inhibition of COX-1-derived thromboxane B(2) synthesis after blood coagulation. Using the ratio of the COX-1 IC(50) values over the COX-2 IC(50) values in the human whole blood assay, selectivity ratios for the inhibition of COX-2 of 36, 6.6, 2, 3, and 0.4 were obtained for rofecoxib, celecoxib, meloxicam, diclofenac, and indomethacin, respectively. In several in vivo rodent models, rofecoxib is a potent inhibitor of carrageenan-induced paw edema (ID(50) = 1.5 mg/kg), carrageenan-induced paw hyperalgesia (ID(50) = 1.0 mg/kg), lipopolysaccharide-induced pyresis (ID(50) = 0.24 mg/kg), and adjuvant-induced arthritis (ID(50) = 0.74 mg/kg/day). Rofecoxib also has a protective effect on adjuvant-induced destruction of cartilage and bone structures in rats. In a (51)Cr excretion assay for detection of gastrointestinal integrity in either rats or squirrel monkeys, rofecoxib has no effect at doses up to 200 mg/kg/day for 5 days. Rofecoxib is a novel COX-2 inhibitor with a biochemical and pharmacological profile clearly distinct from that of current nonsteroidal anti-inflammatory drugs and represents a new therapeutic class of anti-inflammatory agents for the treatment of the symptoms of osteoarthritis and rheumatoid arthritis with improved gastrointestinal tolerability.
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The discovery of rofecoxib, [MK 966, Vioxx, 4-(4'-methylsulfonylphenyl)-3-phenyl-2(5H)-furanone], an orally active cyclooxygenase-2-inhibitor. Bioorg Med Chem Lett 1999; 9:1773-8. [PMID: 10406640 DOI: 10.1016/s0960-894x(99)00288-7] [Citation(s) in RCA: 361] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The development of a COX-2 inhibitor rofecoxib (MK 966, Vioxx) is described. It is essentially equipotent to indomethacin both in vitro and in vivo but without the ulcerogenic side effect due to COX-1 inhibition.
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Abstract
Cyclopentenones containing a 4-(methylsulfonyl)phenyl group in the 3-position and a phenyl ring in the 2-position are selective inhibitors of cyclooxygenase-2 (COX-2). The selectivity for COX-2 over COX-1 is dramatically improved by substituting the 2-phenyl group with halogens in the meta position or by replacing the phenyl ring with a 2- or 3-pyridyl ring. Thus the 3,5-difluorophenyl derivative 7 (L-776,967) and the 3-pyridyl derivative 13 (L-784,506) are particularly interesting as potential antiinflammatory agents with reduced side-effect profiles. Both exhibit good oral bioavailability and are potent in standard models of pain, fever, and inflammation yet have a much reduced effect on the GI integrity of rats compared to standard nonsteroidal antiflammatory drugs.
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4-Chloro-2-{4-[ p-(methylsulfonyl)phenyl]-2-oxo-5-phenyl-2,3-dihydro-1,3-oxazol-3-yl}phenyl Acetate. Acta Crystallogr C 1998. [DOI: 10.1107/s0108270198003928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Statistical mechanics of Kerr-Newman dilaton black holes and the bootstrap condition. Int J Clin Exp Med 1998. [DOI: 10.1103/physrevd.57.1309] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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From indomethacin to a selective COX-2 inhibitor. Development of indolalkanoic acids as potent and selective cyclooxygenase-2 inhibitors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1997; 407:73-8. [PMID: 9321934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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From indomethacin to a selective COX-2 inhibitor: Development of indolalkanoic acids as potent and selective cyclooxygenase-2 inhibitors. Bioorg Med Chem Lett 1996. [DOI: 10.1016/0960-894x(96)00100-x] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Synthesis and biological evaluation of both enantiomers of L-761,000 as inhibitors of cyclooxygenase 1 and 2. Bioorg Med Chem Lett 1996. [DOI: 10.1016/0960-894x(96)00101-1] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Discovery of L-740,515, a potent thienopyridine cysLT1 receptor (LTD4 receptor) antagonist. Bioorg Med Chem Lett 1995. [DOI: 10.1016/0960-894x(95)00448-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
Jupiter's nonthermal microwave emission, as measured by a global network of 11 radio telescopes, increased dramatically during the Shoemaker-Levy 9 impacts. The increase was wavelength-dependent, varying from approximately 10 percent at 70 to 90 centimeters to approximately 45 percent at 6 and 36 centimeters. The radio spectrum hardened (flattened toward shorter wavelengths) considerably during the week of impacts and continued to harden afterward. After the week of cometary impacts, the flux density began to subside at all wavelengths and was still declining 3 months later. Very Large Array and Australia Telescope images of the brightness distribution showed the enhancement to be localized in longitude and concentrated near the magnetic equator. The evidence therefore suggests that the increase in flux density was caused by a change in the resident particle population, for example, through an energization or spatial redistribution of the emitting particles.
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Discovery of MK-0476, a potent and orally active leukotriene D4 receptor antagonist devoid of peroxisomal enxyme induction. Bioorg Med Chem Lett 1995. [DOI: 10.1016/0960-894x(95)00023-m] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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On the Nature of Extended Black Objects. Ann N Y Acad Sci 1993; 688:454-5. [DOI: 10.1111/j.1749-6632.1993.tb43917.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Statistical mechanics of black holes. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1992; 46:2334-2340. [PMID: 10015162 DOI: 10.1103/physrevd.46.2334] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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The discovery of a new structural class of potent orally active leukotriene D4 antagonists. Bioorg Med Chem Lett 1992. [DOI: 10.1016/s0960-894x(00)80635-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Aharonov-Bohm phase shifts for strings interacting with axions. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1992; 45:2880-2882. [PMID: 10014678 DOI: 10.1103/physrevd.45.2880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Calcium mobilization and right-angle light scatter responses to 12-oxo-derivatives of arachidonic acid in neutrophils: evidence for the involvement of the leukotriene B4 receptor. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1133:102-6. [PMID: 1661162 DOI: 10.1016/0167-4889(91)90247-u] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The biological activities of two carbonyl compounds derived from arachidonic acid, (5Z,8Z,10E,14Z)-12-keto-5,8,10,14-eicosatetraeno ic acid (12-OxoETE) and (5Z,8Z,10E)-12-oxo-5,8,10-dodecatrienoic acid (12-OxoDTrE) were investigated. The ability of these compounds to induce a mobilization of calcium and to trigger a right-angle scatter response in isolated peripheral blood human neutrophils was determined. The two compounds induced a rapid and dose-dependent increase in the concentration of cytoplasmic free calcium; these effects were clearly detectable at concentrations greater than or equal to 10(-8) M. Pre-exposure of neutrophils to leukotriene B4 completely abolished the calcium mobilization induced by 12-OxoDTre and 12-OxoETE, while pre-exposure of the cells to the carbonyl compounds only slightly reduced the response to subsequent stimulation of neutrophils by leukotriene B4. The carbonyl compounds also induced a decrease in right-angle light scatter and these effects were abolished by pretreatment of neutrophils with leukotriene B4. These data demonstrate that 12-OxoETE and 12-OxoDTrE show significant agonist activities towards human neutrophils and strongly suggest that their mechanisms of action involve the leukotriene B4 binding sites or a common activation sequence.
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Emission characteristics and source location of the smooth Neptunian kilometric radiation. ACTA ACUST UNITED AC 1991. [DOI: 10.1029/91ja01702] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Stereoselective carbonyl reductases from rat skin and leukocyte microsomes converting 12-ketoeicosatetraenoic acid to 12(S)-HETE. FEBS Lett 1990; 262:197-200. [PMID: 2185947 DOI: 10.1016/0014-5793(90)80188-o] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cell-free preparations from rat polymorphonuclear leukocytes and skin were found to catalyze the reduction of 12-keto-5,8,10,14-eicosatetraenoic acid (12-KETE) to 12-hydroxyeicosatetraenoic acid (12-HETE). The reductase activity was associated with the microsomal fraction and showed a marked preference for NADH over NADPH as reducing cofactor. Characterization of the reaction product by chiral phase HPLC of the methyl ester derivative indicated that 12-KETE reduction generated almost exclusively 12(S)-HETE. The results demonstrate that rat skin and leukocyte microsomes possess an NADH-dependent 12-KETE reductase activity that forms 12(S)-HETE as a major product. The identification of stereoselective 12-KETE reductases provides a basis for further defining the role these enzymes may play in the regulation of 12-KETE levels and in the protection against degradation of 12-KETE to the pro-inflammatory 12(R)-HETE by selectively generating 12-HETE of the S configuration.
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Generalized McClain-Roth-O'Brien-Tan theorem and the string free energy at higher genus. PHYSICAL REVIEW LETTERS 1990; 64:831-834. [PMID: 10042092 DOI: 10.1103/physrevlett.64.831] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Improved integral representation for the finite-temperature propagator in string theory. Int J Clin Exp Med 1989; 39:1139-1151. [PMID: 9959751 DOI: 10.1103/physrevd.39.1139] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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NAD(P)H-dependent reduction of 12-ketoeicosatetraenoic acid to 12(R)- and 12(S)-hydroxyeicosatetraenoic acid by rat liver microsomes. Biochem Biophys Res Commun 1988; 156:1083-9. [PMID: 3190686 DOI: 10.1016/s0006-291x(88)80743-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The possibility that 12-keto-5,8,10,14 eicosatetraenoic acid (12-KETE) could be used as substrate by reductase(s) to generate 12-hydroxyeicosatetraenoic acid (12-HETE) was investigated using rat liver microsomes as a source of enzyme activity. Microsomes catalyzed the time-dependent reduction of 12-KETE to 12-HETE in a reaction that required NAD(P)H. The maximal specific activity of 12-HETE formation was 1.7 nmol/min/mg of protein in the presence of NADH. The reaction could not be detected in the absence of cofactor or by using heat inactivated microsomes. The identity of the 12-HETE product was established by U.V. spectroscopy and co-elution with 12-HETE in two different systems of RP-HPLC. Resolution of the methyl esters of reaction products by chromatography on chiral columns also indicated that the reduction of 12-KETE with either NADPH or NADH generated a mixture of 12(S)- and 12(R)-HETE in a ratio of about 2:1. The results demonstrate the presence of a 12-KETE reductase activity in rat liver microsomes which can form both the R and S isomers of 12-HETE.
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Cosmological aspects of the heterotic string above the Hagedorn temperature. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1988; 38:3087-3093. [PMID: 9959053 DOI: 10.1103/physrevd.38.3087] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Quality assurance for pharmacy services in a long term care hospital. Can J Hosp Pharm 1988; 41:149-51. [PMID: 10288500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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String field theory at finite temperature. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1987; 36:1780-1793. [PMID: 9958362 DOI: 10.1103/physrevd.36.1780] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Analogs of leukotriene B4: effects of modification of the hydroxyl groups on leukocyte aggregation and binding to leukocyte leukotriene B4 receptors. PROSTAGLANDINS 1987; 33:617-25. [PMID: 3035618 DOI: 10.1016/0090-6980(87)90029-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The syntheses and agonist and binding activities of 5(S)-hydroxy- 6(Z), 8(E), 10(E), 14(Z)-eicosatetraenoic acid (12-deoxy LTB4), 5(S), 12(S)-dihydroxy-6(Z), 8(E), 10(E), 14(Z)-eicosatetraenoic acid (12-epi LTB4), 12(R)-hydroxy-6(Z), 8(E), 10(E), 14(Z)-eicosatetraenoic acid (5-deoxy LTB4), 5(R), 12(S)-dihydroxy-6(Z), 8(E), 10(E), 14(Z)-eicosatetraenoic acid (5-epi LTB4), 6(Z), 8(E), 10(E), 14(Z)-eicosatetraenoic acid (5, 12-deoxy LTB4) are described. These leukotriene B4 analogs were all able to aggregate rat leukocytes and compete with [3H]-leukotriene B4 for binding to rat and human leukocyte leukotriene B4 receptors with varying efficacy. The analog in which the 12-hydroxyl group was removed was severely reduced both in agonist action (aggregation) and binding. The epimeric 12-hydroxyl analog demonstrated better agonist and binding properties than the analog without a hydroxyl at this position. In contrast, in the case of the 5-hydroxyl the epimeric hydroxyl analog had greatly reduced agonist and binding activities while the 5-deoxy analog demonstrated potency only several fold less than leukotriene B4 itself. The dideoxy leukotriene B4 analog was more than a thousand fold less active than leukotriene B4 as an agonist and in binding to the leukotriene B4 receptor. These results show that binding to the leukocyte leukotriene B4 receptor requires a hydroxyl group at the 12 position in either stereochemical orientation but that the presence of a hydroxyl at the 5 position is less important. However, the epimeric C5 leukotriene B4 analog clearly interacts unfavourably with the binding site of the leukotriene B4 receptor.
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Activation of leukocyte movement and displacement of [3H]leukotriene B4 from leukocyte membrane preparations by (12R)- and (12S)-hydroxyeicosatetraenoic acid. BIOCHIMICA ET BIOPHYSICA ACTA 1987; 917:406-10. [PMID: 3026490 DOI: 10.1016/0005-2760(87)90119-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Both (12R)- and (12S)-hydroxyeicosatetraenoic acid were demonstrated to produce aggregation of rat leukocytes and enhance human leukocyte chemokinesis. (12R)-Hydroxyeicosatetraenoic acid was 10-20-fold more potent than (12S)-hydroxyeicosatetraenoic acid but at least 500-fold less potent than leukotriene B4 in these assays. These relative potencies are correlated with the potencies of (12R)- and (12S)-hydroxyeicosatetraenoic acid for competition of [3H]leukotriene B4 binding to rat and human leukocyte membrane preparations.
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